Preparation of super-hydrophobic/super-oleophilic quartz sand filter for the application in oil-water separation

In the present work, novel super-hydrophobic/super-oleophilic surface of quartz sand was prepared by constructing silica rough structure and modifying it with low-surface-energy hexadecyl-trimethoxysilane (HDTMS). The characterization results revealed that the water contact angle (WCA) of the modified quartz sand was more than 150° and the oil contact angle (OCA) was nearly 0°. Notably, the modified quartz sand could be used as a filter to separate oil and water and depicted a high separation efficiency. The water content in the filtrate was less than 0.5 wt%. In the meantime, the modified quartz sand can fully separate the oil film from water by adhesion. The WCA of the modified quartz sand remains above 148° even after repeated test, which indicated that the modified quartz sand had good stability and reusability.